X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=nodestack.cc;h=a39701eaf871c90a7da3b41e2f296421dd4d6186;hb=c01d975387b4fc4b711acbdbdc19e3690985adec;hp=d3b7c104316161d0268c8ae1b2db7a116fbbac74;hpb=87273fd76240454e85a233c34b93463fa681480b;p=model-checker.git

diff --git a/nodestack.cc b/nodestack.cc
index d3b7c10..a39701e 100644
--- a/nodestack.cc
+++ b/nodestack.cc
@@ -24,10 +24,12 @@ Node::Node(ModelAction *act, Node *par, int nthreads)
 	explored_children(num_threads),
 	backtrack(num_threads),
 	numBacktracks(0),
-	may_read_from()
+	may_read_from(NULL)
 {
 	if (act)
 		act->set_node(this);
+	if (act && act->is_read())
+		may_read_from = new action_set_t();
 }
 
 /** @brief Node desctructor */
@@ -119,7 +121,8 @@ bool Node::is_enabled(Thread *t)
  */
 void Node::add_read_from(ModelAction *act)
 {
-	may_read_from.insert(act);
+	ASSERT(may_read_from);
+	may_read_from->insert(act);
 }
 
 void Node::explore(thread_id_t tid)